(***********************************************************************)
(*                                                                     *)
(*                               TAToo                                 *)
(*                                                                     *)
(*                   Lucca Hirschi, LRI UMR8623                        *)
(*                   Université Paris-Sud & CNRS                       *)
(*                                                                     *)
(*  Copyright 2010-2012 Université Paris-Sud and Centre National de la *)
(*  Recherche Scientifique. All rights reserved.  This file is         *)
(*  distributed under the terms of the GNU Lesser General Public       *)
(*  License, with the special exception on linking described in file   *)
(*  ../LICENSE.                                                        *)
(*                                                                     *)
(***********************************************************************)

module Node  =
struct
  type t = int
  let hash n = n
  let compare = (-)
  let equal = (=)
end
  
module NodeHash = Hashtbl.Make (Node)
  
type t = (StateSet.t*StateSet.t) NodeHash.t
(** Map from nodes to query and recognizing states *)
(* Note that we do not consider nil nodes *)

exception Oracle_fail
exception Over_max_fail
exception Max_fail

(* Mapped sets for leaves *)
let map_leaf asta = (Asta.bot_states_s asta, StateSet.empty)

(* Build the Oracle *)
let rec bu_oracle asta run tree tnode =
  let node = Tree.preorder tree tnode in
  if Tree.is_leaf tree tnode
  then
    if tnode == Tree.nil
    then ()
    else NodeHash.add run node (map_leaf asta)
  else
    let tfnode = Tree.first_child_x tree tnode
    and tnnode = Tree.next_sibling tree tnode in
    let fnode,nnode =                            (* their preorders *)
      (Tree.preorder tree tfnode, Tree.preorder tree tnnode) in
    begin
      bu_oracle asta run tree tfnode;
      bu_oracle asta run tree tnnode;
      let q_rec n =                     (* compute the set for child/sibling *)
        try NodeHash.find run n
        with Not_found -> map_leaf asta in
      let (_,qfr),(_,qnr) = q_rec fnode,q_rec nnode (* computed in rec call *)
      and lab = Tree.tag tree tnode in
      let _,list_tr = Asta.transitions_lab asta lab in (* only reco. tran.*)
      let rec result set flag = function (* add states which satisfy a transition *)
        | [] -> set,flag
        | (q,form) :: tl ->
          if Formula.eval_form (set,qfr,qnr) form (* evaluates the formula*)
          then
            if StateSet.mem q set
            then result set 0 tl
            else result (StateSet.add q set) 1 tl
          else result set 0 tl in
      let rec fix_point set_i =  (* compute the fixed point of states of node *)
        let set,flag = result set_i 0 list_tr in
        if flag = 0 then set
        else fix_point set in
      NodeHash.add run node (StateSet.empty, fix_point StateSet.empty)
    end
      
(* Build the over-approx. of the maximal run *)
let rec bu_over_max asta run tree tnode =
  if (Tree.is_leaf tree tnode)      (* BU_oracle has already created the map *)
  then
    ()
  else
    let tfnode = Tree.first_child_x tree tnode
    and tnnode = Tree.next_sibling tree tnode in
    begin
      bu_over_max asta run tree tfnode;
      bu_over_max asta run tree tnnode;
      let (fnode,nnode) =
        (Tree.preorder tree tfnode, Tree.preorder tree tnnode)
      and node = Tree.preorder tree tnode in          
      let q_rec n =
        try NodeHash.find run n
        with Not_found -> map_leaf asta in
      let qf,qn = q_rec fnode,q_rec nnode in
      let lab = Tree.tag tree tnode in
      let list_tr,_ = Asta.transitions_lab asta lab (* only take query st. *)
      and _,resultr = try NodeHash.find run node
        with _ -> raise Over_max_fail in      
      let rec result set flag = function
        | [] -> if flag = 0 then set else result set 0 list_tr
        | (q,form) :: tl ->
          if StateSet.mem q set
          then result set 0 tl
          else if Formula.infer_form (set,resultr) qf qn form
               then result (StateSet.add q set) 1 tl
               else result set 0 tl in
      let result_set = result StateSet.empty 0 list_tr in
      (* we keep the old recognizing states set *)
      NodeHash.replace run node (result_set, resultr)
    end


(* Build the maximal run *)
let rec tp_max asta run tree tnode =
  if (Tree.is_leaf tree tnode)      (* BU_oracle has already created the map *)
  then
    ()
  else
    let node = Tree.preorder tree tnode
    and tfnode = Tree.first_child_x tree tnode
    and tnnode = Tree.next_sibling tree tnode in
    let (fnode,nnode) =
      (Tree.preorder tree tfnode, Tree.preorder tree tnnode) in
    begin
      if tnode == Tree.root tree        (* we must intersect with top states *)
      then let setq,_  = try NodeHash.find run node
        with _ -> raise Max_fail in
           NodeHash.replace run node
             ((StateSet.inter (Asta.top_states_s asta) setq),StateSet.empty)
      else ();
      let q_rec n =
        try NodeHash.find run n
        with Not_found -> map_leaf asta in
      let qf,qn = q_rec fnode,q_rec nnode in
      let lab = Tree.tag tree tnode in
      let list_tr,_ = Asta.transitions_lab asta lab in (* only take query. *)
      let (self_q,self_r) = try NodeHash.find run node
        with Not_found -> raise Max_fail in

      (* We must compute again accepting states from self transitions since
         previous calls of tp_max may remove them *)
      let rec result_q self_q queue = function (* for initializing the queue *)
        | [] -> self_q,queue
        | (q,form) :: tl ->
          if (StateSet.mem q self_q)
          then begin 
            let q_cand,_,_ = Formula.st form in
            StateSet.iter (fun x -> Queue.push x queue) q_cand;
            result_q (StateSet.add q self_q) queue tl;
          end
          else result_q self_q queue tl
      and result_st_q self_q queue flag = function (*for computing the fixed p*)
        | [] -> flag,queue
        | form :: tl ->
          if Formula.infer_form (self_q,self_r) qf qn form
          then begin 
            let q_cand,_,_ = Formula.st form in
            StateSet.iter (fun x -> Queue.push x queue) q_cand;
            result_st_q self_q queue 1 tl;
          end
          else result_st_q self_q queue flag tl in
      let rec comp_acc_self self_q_i queue = (* compute the fixed point *)
        if Queue.is_empty queue
        then self_q_i
        else
          let q = Queue.pop queue in
          let list_q,_ = Asta.transitions_st_lab asta q lab in
          let flag,queue = result_st_q self_q_i queue 0 list_q in
          let self_q = if flag = 1 then StateSet.add q self_q_i else self_q_i in
          comp_acc_self self_q queue in
      
      let self,queue_init = result_q self_q (Queue.create()) list_tr in
      let self_q = comp_acc_self self_q queue_init in
      NodeHash.replace run node (self_q,self_r);
      (* From now, the correct set of states is mapped to node! *)
      let rec result = function
        | [] -> []
        | (q,form) :: tl ->
          if (StateSet.mem q self) &&  (* infers & trans. can start here *)
            (Formula.infer_form (self_q,self_r) qf qn form)
          then form :: (result tl)
          else result tl in      
      let list_form = result list_tr in (* tran. candidates *)
      (* compute states occuring in transition candidates *)
      let rec add_st (ql,qr) = function
        | [] -> ql,qr
        | f :: tl -> let sqs,sql,sqr = Formula.st f in
                     let ql' = StateSet.union sql ql
                     and qr' = StateSet.union sqr qr in
                     add_st (ql',qr') tl in
      let ql,qr = add_st (StateSet.empty, StateSet.empty) list_form in
      let qfq,qfr = try NodeHash.find run fnode
        with | _ -> map_leaf asta
      and qnq,qnr = try NodeHash.find run nnode
        with | _ -> map_leaf asta in
      begin
        if tfnode == Tree.nil || Tree.is_attribute tree tnode
        then ()
        else NodeHash.replace run fnode (StateSet.inter qfq ql,qfr);
        if tnnode == Tree.nil || Tree.is_attribute tree tnode
        then ()
        else NodeHash.replace run nnode (StateSet.inter qnq qr,qnr);
        (* indeed we delete all states from self transitions!  *)
        tp_max asta run tree tfnode;
        tp_max asta run tree tnnode;
      end;
    end
        
let compute tree asta =
  let flag = 2 in                       (* debug  *)
  let size_tree = 10000 in              (* todo (Tree.size ?) *)
  let map = NodeHash.create size_tree in
  bu_oracle asta map tree (Tree.root tree);
  if flag > 0 then begin
    bu_over_max asta map tree (Tree.root tree);
    if flag = 2
    then
      tp_max asta map tree (Tree.root tree)
    else ()
  end
  else ();
  map

let selected_nodes tree asta =
  let run = compute tree asta in
  NodeHash.fold
    (fun key set acc ->
      if not(StateSet.is_empty
               (StateSet.inter (fst set) (Asta.selec_states asta)))
      then key :: acc
      else acc)
    run []

let print fmt run =
  let print_d_set fmt (s_1,s_2) =
    Format.fprintf fmt "(%a,%a)"
      StateSet.print s_1 StateSet.print s_2 in
  let print_map fmt run =
    let pp = Format.fprintf fmt in
    if NodeHash.length run = 0
    then Format.fprintf fmt "ø"
    else
      NodeHash.iter (fun cle set -> pp "|  %i->%a  @ " cle print_d_set set)
        run in
  let print_box fmt run =
    let pp = Format.fprintf fmt in
    pp "@[<hov 0>@.  # Mapping:@.   @[<hov 0>%a@]@]"
      print_map run
  in
  Format.fprintf fmt "@[<hov 0>##### RUN #####@, %a@]@." print_box run